Electric conductor.



PATENTED FEB. 26, 1907.

S. G. BROWN. ELECTRIC, UONDUOTOR.

APPLICATION FILED JUNE 16, 1902.

UNITED STATES- PATENT oriuon.

SIDNEY GEORGE BROWN; OF LONDONQENGLAND.

ELECTRIC CONDUCTOR-b v No. 845,609.

To all whom it may concern:

Be it known that I, SIDNEY GEORGE BROWN, a subject of the King of Great Britain, residing at 4 Great Winchester. street, in the county of London, England,

tion.

This invention relates to improvements in duplex line conductors for the telegraph and telephone purposes in which the self-induct- I ance will balance the capacity, thus leaving only the resistance effect to be dealt with, and thereby increasing the speed and efiiciency of the signaling by electric-wave propagation. f

Accordin to this invention I overcome the effect 0 capacity of the line or cable by placing self-inductance in a continuous manner along the core of said line or cable. For this purpose I surround a central insulated core with a preferably spiral-wound conductor having its turns insulated from one another, and I coat said conductor with gutta-percha or other suitable insulator.

According to the form of construction which I prefersay for a submarine cable I employ a central core which may be of iron or steel wire broken into lengths, if found necessary, to prevent electrostatic charges running along the core, "or said central core may be a jute, hemp, or similar cord constitutm an air-core. This central core is surroun ed by paper or other insulation material saturated, if necessary, inoilor Wax. Outside the paper or other insulation material I place thev preferably spirally-twisted 00 per conductor, the turns of which are insul ated from one another by cotton, silk, paper, or other suitable material and which may consist of two or more strands. ThlS conductor may advantageously be of square or rectangular cross-section. The twisted conductor is covered with gutta-percha,

which is in turn covered by jute-yarn steeped I in cute or other preservative, and the cable may be provided with a steel-wire sheathing or armor.

ln c0nstructing a land-wire for telephone or telegra h purposes the jute or similar material an the sheathing or armor may be Specification of Letters latent. Application filed June 16', 1902. Serial No. 111,964.

iatented Feb. 26, 1907.

' omitted, the central coretaking the stress and acting as-a return-conductor.

When the central core 1s of ron, it serves to'strengthen the cable or line and alsoacts as amagnetic materialto increase the self-- inductance of the twisted conductor. The tWlSt'Qd conductor. constitutes the winding of an inductance-coil, and thus provides selfinductance-1n a continuous manner along the cable or line. Y

To duplex the line' or cable,- I may employ any suitable form of Wheatstone bridge; but

duction, and resistance and must be made to imitate as far as possible the pro erties of said cable or line. To effect this, may arrange the artificial line-boxes according. to Stearns well-known method; but the resists :the artificial line must possess capacity, in-

ance. between the capacities emplo ed should be made self-inductive in such va ue in roportionto the capacity and resistance 0 the artificial line as to imitate its equivalent length of cable; The induction in the first portion of the artificial'line must be es ecially carefully distributed. I may make t 's artificial line by winding atin-foil strip round a cardboard roller of suitable dimensions, an insulated tin-foil sheet to act as earth-plate bein placed underthe strip and over the cardboard and insulated from said strip. This earth-plate is cut up into lengths, so as not to form a continuous conductor round the cardboard, for which purpose it is preferably split in the direction of the length of the cardboard roller or tube, so as not to interfere with the inductive effect of the strap. In other words, the purpose of the longitu inal slitting is to prevent induced currents being set up in and circulating around the earth-plate. structed would possess, first, capacity due to the effect between the strip and the earthplate; second, resistance due to the length of the strip, and, third, induction, because the strip'is spirally wound. All these three effects should be proportioned in accordance with the cable or line which it is intended to copy. 7

During the manufacture of the cable or line it is essential to practical success to test short lengths in order to insure that the self-induction balances the electrostatic effect or capacity.

An artificial line thus con Referring to the drawings, Figure 1 shows the cable, parts of which'are removed to expose the core, the conductor, and the insulation material. on an enlarged sca e. Fig. 3 is a cross-sec tion through one of the turns of the conductor. Fig. 4 illustrates the construction of the artificial line. Fig. 5 is a diagram illustrating the duplexing of the cable. Fig. 6 is a View of a modified form of conductor.

1 is the central iron or steel core surround.

ed by paper 2. i

3 is a spirally-Wound copper conductor having its turns insulated fromone another by cotton, silk, or other suitable material 4 and covered by gutta-percha or other suitable insulator 5. This insulator 5 is protected by jute-yarn 6, steeped in cutch, and the cable thus constructed is armored in the wellknown manner by iron or steel wire '7 and an outer covering 8, or the core may be protect ed in any other suitable manner. In some cases a brass tape 9 is Wound round the insulator 5.

It is obvious that instead ofv consisting of a single strand, as shown, the conductor 3 might consist of, several strands, either placed side by side or superposed one upon the other, and that these strands might be either all inclosed in one insulating-cover or each strand might be separately insulated.

In using the cable for a land-line the covering 5, 6, 7, 8, and 9 may be omitted, the central core acting as asupport and, if necessary, as the return-conductor, or the return-c onductor may be another conductor similar to, but

placed over, the conductor 3 and wound in the opposite direction thereto. The outgo ing and return currents will then both produce inductive effects; Such a double-wound conductor may be suitably covered and protected to act as a submarine or subterranean cable.

The signaling-currents pass through the conductor 3, producing electric waves along the core, which waves operate the receiving apparatus at the far end of the cable.

By spirally twisting the conductor 3, as above described, it is made self-inductive and the effect of capacity of the line is overcome.

Referring to Fig. 4, 10 is the cardboard roller, upon which is placed a longitudinallyslotted insulated tin-foil plate 11, connected to earth E. 12 is the spirally-wound tin-foil strip included in the line or cable circuit. This spirally-wound strip is suitably insulated from the tin-foil 11. In manufactur ing this artificial line it is convenient to then cover the strip 12 with insulating material, to place a second earth-plate similar to the earth-plate 11 over said insulating material, and a second tin-foil strip, such as 12, over the earth-plate. In this manner the size of Fi 2 shows the conductor.

the artificial line may be conveniently in- Referring to Fig. 5, the conductor 3 is con-- nected to one arm 13 of a Wheatstone bridge, the other arm 14 of which is connected to the artificial line. The apex of the bridge is connected to the transmitter 15. The receiver 16 is placed across the arms of the bridge, and 17 17 are the usual condensers. two' sections of the artificial line are constructed as shown in Fig. 4, and the sections of thelatter end of the artificial line may convenien-tly comprise condensers 18, connected to-earth E, and self-inductively-wound resistances 19.

In. the form of embodiment of the invenslightly-modified form of conductor, 1 designates the iron core, 2. a spiral conductor, and 3 a returnconductor, with its twists disposed opposite to the conductor2.

8o tion shown in Fig. 6, which illustrates a It is essential to practical success to test the cable and artificial line in short lengthssay of one mileduri manufacture to insure that the capacity is alanced by the selfinduction.

What I claim, and desire to secure by Ltters Patent of the United States, is-

1'. In an electric cable or line, the combina- 4 tion of a magnetic core, a spirally-wound conductor surrounding said core, material for insulatin the turns ofsaid conductor from one another, a covering of. insulating substance surrounding said insulated conductor, and an artificial line included in the circuit of said cable or line and comprising a cardboard core, an insulated earth-plate surrounding said core, and a spirally-Wound insulated conductor surrounding said earthplate, substantially as and for the purpose specified.

2. In an electric cable or line, the combination of a magnetic core, a s pirally-wound conplate, substantially as and for the purpose specified.

3. The combination of a cable having balanced capacity and self-induction, and an artificial cable comprising a core, an earthplate,- and a self-inductively-wound resistance surrounding but insulated from said earth-plate, substantially as described.

4. The combination of a cable having bal- In testimony whereof I have hereunto set my hand ,in presence of two subscribing W1t- 1 .nesses, this 3d day of June, 1902.

SIDNEY GEORGE BROWN.

Witnesses:

'1. SELLY WARD, WALTER J. SKERTEN,

anced capacity and self-inductance and an artificial line having an-earth-plate and a spirally-Wound insulated conductor surrounding the same, substantially as described.

5 5. The combination of a cable having cav pacit and self-inductance, and an artificial line aving an earth-plate and a spirallywound conductor surrounding the same. 

